From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755043AbYGUTVn (ORCPT ); Mon, 21 Jul 2008 15:21:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754125AbYGUTVe (ORCPT ); Mon, 21 Jul 2008 15:21:34 -0400 Received: from smtp.extricom.com ([192.114.46.18]:57594 "HELO smtp.extricom.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753560AbYGUTVd (ORCPT ); Mon, 21 Jul 2008 15:21:33 -0400 Message-ID: <4884E0FB.9010909@extricom.com> Date: Mon, 21 Jul 2008 22:18:19 +0300 From: Eran Liberty User-Agent: Thunderbird 2.0.0.14 (X11/20080502) MIME-Version: 1.0 To: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org CC: Jesse Barnes , eran.liberty@gmail.com Subject: [PATCH 2.6.26] PCI: refuse to re-add a device to a bus upon pci_scan_child_bus() References: <48591941.4070408@extricom.com> In-Reply-To: <48591941.4070408@extricom.com> Content-Type: multipart/mixed; boundary="------------010007000203040801020203" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------010007000203040801020203 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Dear Penguins, As a follow up on my own post ( http://lkml.org/lkml/2008/6/18/195 ), I have solved a small bug/misbehavior within the pci_scan_single_device(). The misbehavior manifest itself upon calling pci_scan_child_bus() with a bus which already contain some devices. After scanning is done devices that already existed will be present twice in the PCI bus devise list. Once with is_added indication and once without. Trying to add this bus will cause a resource conflict as the same device is already present and initialized. This patch will simply prevent a device to be added to a pci bus list if it is already there. Points to consider: 1. I am not a PCI Guru and might have over looked the bigger picture. Is it OK to prevent a device of being re-added? 2. I have decided that two devices are, in fact, the same instance if it has the same: vendor, device, and devfn. Is there a finer test for a device identity? p.s. As per http://www.kernel.org/pub/linux/docs/lkml/#s1-10 it is preferred for Mozilla Firefox clients to attach the patch, hence my patch is attached. Liberty Signed-off-by: Eran Liberty --- --------------010007000203040801020203 Content-Type: text/x-patch; name="refuse_readd_pci_device.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="refuse_readd_pci_device.patch" drivers/pci/probe.c | 10 ++++++++++ 1 files changed, 10 insertions(+), 0 deletions(-) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index b1724cf..e3c3ee0 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1002,11 +1002,21 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus) struct pci_dev *__ref pci_scan_single_device(struct pci_bus *bus, int devfn) { struct pci_dev *dev; + struct list_head *ln; dev = pci_scan_device(bus, devfn); if (!dev) return NULL; + /* refuse to re-add a device */ + list_for_each(ln, &bus->devices) { + struct pci_dev *d = pci_dev_b(ln); + if ((d->vendor == dev->vendor) && + (d->device == dev->device) && + (d->devfn == dev->devfn)) + return NULL; + } + pci_device_add(dev, bus); return dev; --------------010007000203040801020203--